1. Field of the Invention
The present invention generally relates to the field of etching a film deposited on a sample, such as a semiconductor device. More particularly, it relates to mechanisms for dry etching at low temperatures.
2. Description of Related Art
One technique for dry etching a sample is referred to as reactive ion etching. In theory, the ions react with the surface material of the sample to form an evaporative material that thereby evaporates from the sample. However, there are problems associated with dry etching some materials, such as copper. In the case of copper, when the copper is bombarded with Cl-containing reactive gases, a copper chloride material, CuClx, is formed over the surface of the copper. This chloride material fails to evaporate well at room temperatures. Accordingly, the sample needs to be heated to temperatures that are significantly higher than room temperature to facilitate evaporation of the CuClx material. For example, the substrate of sample must be heated to above 200° C. in order to etch Cu films. In many cases, a conventional dry etch process prevents the sample from being used in production since the high temperatures tend to damage the sample.
Consequently, improved techniques and systems for etching materials, such as Cu, to produce fine patterns at low temperature are needed. Additionally, techniques and systems for etching samples which do not destroy the sample are needed. Preferably, a dry etching mechanism that works at room temperatures for materials which cannot be conventionally dry etched at room temperatures is needed.